A few hours after MegaChat had been released, he tweeted the site already had over 500,000 calls, and recently Dotcom tweeted, “#Mega has over 15 million registered users now. I think #MegaChat could elevate us to 100+ million users by the end of 2015. #Prediction.”

Dotcom says what sets MegaChat apart from competitors such as Skype is that it uses end-to-end encryption, so users’ information remains private.

In December, when Dotcom revealed his plans to launch MegaChat, he said, “No US based online service provider can be trusted with your data. Skype has no choice. They must provide the US Government with backdoors.”

End-to-end encryption protects communications from upstream surveillance, but only if there are no bugs or backdoors in the implementation.

MegaChat’s implementation has not yet been looked into by security researchers and cryptography experts.

In the past Skype came under fire when information surfaced that the National Security Agency (NSA) could wiretap Skype audio and video chats.

However, Skype says they do use encryption for Skype-to-Skype voice, video, file transfers and instant messages. “This protects you from potential eavesdropping by malicious users,” says Skype.

Dotcom acknowledges that in the beta version of the service there are bound to be bugs. “#Mega offers a security bounty again. Please report any security flaw to us. We’ll fix it and reward you. Thanks for helping,” he said via Twitter.

The US has been trying to extradite Dotcom from New Zealand so he can face charges for copyright infringement and other offences in relation to MegaUpload, his former video streaming site.

Dotcom acknowledged MegaUpload with a tweet that reads, “3 years ago #Megaupload died, 2 years ago #Mega was born, 1 year ago the Internet Part, Today you get #MegaChat, @MPAA, @TheJusticeDept @NSA.”